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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network218.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
218.0.0.0
Broadcast address
218.255.255.255
First usable
218.0.0.1
Last usable
218.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex DA000000 · Integer 3657433088 to 3674210303
Reverse DNS zone
218.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011010..00000000.00000000.00000000218.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11011010..00000000.00000000.00000000218.0.0.0
Broadcast11011010..11111111.11111111.11111111218.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

218.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1218.0.0.0/19218.0.0.1 to 218.0.31.254218.0.31.2558,190
2218.0.32.0/19218.0.32.1 to 218.0.63.254218.0.63.2558,190
3218.0.64.0/19218.0.64.1 to 218.0.95.254218.0.95.2558,190
4218.0.96.0/19218.0.96.1 to 218.0.127.254218.0.127.2558,190
5218.0.128.0/19218.0.128.1 to 218.0.159.254218.0.159.2558,190
6218.0.160.0/19218.0.160.1 to 218.0.191.254218.0.191.2558,190
7218.0.192.0/19218.0.192.1 to 218.0.223.254218.0.223.2558,190
8218.0.224.0/19218.0.224.1 to 218.0.255.254218.0.255.2558,190
9218.1.0.0/19218.1.0.1 to 218.1.31.254218.1.31.2558,190
10218.1.32.0/19218.1.32.1 to 218.1.63.254218.1.63.2558,190
11218.1.64.0/19218.1.64.1 to 218.1.95.254218.1.95.2558,190
12218.1.96.0/19218.1.96.1 to 218.1.127.254218.1.127.2558,190
13218.1.128.0/19218.1.128.1 to 218.1.159.254218.1.159.2558,190
14218.1.160.0/19218.1.160.1 to 218.1.191.254218.1.191.2558,190
15218.1.192.0/19218.1.192.1 to 218.1.223.254218.1.223.2558,190
16218.1.224.0/19218.1.224.1 to 218.1.255.254218.1.255.2558,190
17218.2.0.0/19218.2.0.1 to 218.2.31.254218.2.31.2558,190
18218.2.32.0/19218.2.32.1 to 218.2.63.254218.2.63.2558,190
19218.2.64.0/19218.2.64.1 to 218.2.95.254218.2.95.2558,190
20218.2.96.0/19218.2.96.1 to 218.2.127.254218.2.127.2558,190
21218.2.128.0/19218.2.128.1 to 218.2.159.254218.2.159.2558,190
22218.2.160.0/19218.2.160.1 to 218.2.191.254218.2.191.2558,190
23218.2.192.0/19218.2.192.1 to 218.2.223.254218.2.223.2558,190
24218.2.224.0/19218.2.224.1 to 218.2.255.254218.2.255.2558,190
25218.3.0.0/19218.3.0.1 to 218.3.31.254218.3.31.2558,190
26218.3.32.0/19218.3.32.1 to 218.3.63.254218.3.63.2558,190
27218.3.64.0/19218.3.64.1 to 218.3.95.254218.3.95.2558,190
28218.3.96.0/19218.3.96.1 to 218.3.127.254218.3.127.2558,190
29218.3.128.0/19218.3.128.1 to 218.3.159.254218.3.159.2558,190
30218.3.160.0/19218.3.160.1 to 218.3.191.254218.3.191.2558,190
31218.3.192.0/19218.3.192.1 to 218.3.223.254218.3.223.2558,190
32218.3.224.0/19218.3.224.1 to 218.3.255.254218.3.255.2558,190
33218.4.0.0/19218.4.0.1 to 218.4.31.254218.4.31.2558,190
34218.4.32.0/19218.4.32.1 to 218.4.63.254218.4.63.2558,190
35218.4.64.0/19218.4.64.1 to 218.4.95.254218.4.95.2558,190
36218.4.96.0/19218.4.96.1 to 218.4.127.254218.4.127.2558,190
37218.4.128.0/19218.4.128.1 to 218.4.159.254218.4.159.2558,190
38218.4.160.0/19218.4.160.1 to 218.4.191.254218.4.191.2558,190
39218.4.192.0/19218.4.192.1 to 218.4.223.254218.4.223.2558,190
40218.4.224.0/19218.4.224.1 to 218.4.255.254218.4.255.2558,190
41218.5.0.0/19218.5.0.1 to 218.5.31.254218.5.31.2558,190
42218.5.32.0/19218.5.32.1 to 218.5.63.254218.5.63.2558,190
43218.5.64.0/19218.5.64.1 to 218.5.95.254218.5.95.2558,190
44218.5.96.0/19218.5.96.1 to 218.5.127.254218.5.127.2558,190
45218.5.128.0/19218.5.128.1 to 218.5.159.254218.5.159.2558,190
46218.5.160.0/19218.5.160.1 to 218.5.191.254218.5.191.2558,190
47218.5.192.0/19218.5.192.1 to 218.5.223.254218.5.223.2558,190
48218.5.224.0/19218.5.224.1 to 218.5.255.254218.5.255.2558,190
49218.6.0.0/19218.6.0.1 to 218.6.31.254218.6.31.2558,190
50218.6.32.0/19218.6.32.1 to 218.6.63.254218.6.63.2558,190
51218.6.64.0/19218.6.64.1 to 218.6.95.254218.6.95.2558,190
52218.6.96.0/19218.6.96.1 to 218.6.127.254218.6.127.2558,190
53218.6.128.0/19218.6.128.1 to 218.6.159.254218.6.159.2558,190
54218.6.160.0/19218.6.160.1 to 218.6.191.254218.6.191.2558,190
55218.6.192.0/19218.6.192.1 to 218.6.223.254218.6.223.2558,190
56218.6.224.0/19218.6.224.1 to 218.6.255.254218.6.255.2558,190
57218.7.0.0/19218.7.0.1 to 218.7.31.254218.7.31.2558,190
58218.7.32.0/19218.7.32.1 to 218.7.63.254218.7.63.2558,190
59218.7.64.0/19218.7.64.1 to 218.7.95.254218.7.95.2558,190
60218.7.96.0/19218.7.96.1 to 218.7.127.254218.7.127.2558,190
61218.7.128.0/19218.7.128.1 to 218.7.159.254218.7.159.2558,190
62218.7.160.0/19218.7.160.1 to 218.7.191.254218.7.191.2558,190
63218.7.192.0/19218.7.192.1 to 218.7.223.254218.7.223.2558,190
64218.7.224.0/19218.7.224.1 to 218.7.255.254218.7.255.2558,190
65218.8.0.0/19218.8.0.1 to 218.8.31.254218.8.31.2558,190
66218.8.32.0/19218.8.32.1 to 218.8.63.254218.8.63.2558,190
67218.8.64.0/19218.8.64.1 to 218.8.95.254218.8.95.2558,190
68218.8.96.0/19218.8.96.1 to 218.8.127.254218.8.127.2558,190
69218.8.128.0/19218.8.128.1 to 218.8.159.254218.8.159.2558,190
70218.8.160.0/19218.8.160.1 to 218.8.191.254218.8.191.2558,190
71218.8.192.0/19218.8.192.1 to 218.8.223.254218.8.223.2558,190
72218.8.224.0/19218.8.224.1 to 218.8.255.254218.8.255.2558,190
73218.9.0.0/19218.9.0.1 to 218.9.31.254218.9.31.2558,190
74218.9.32.0/19218.9.32.1 to 218.9.63.254218.9.63.2558,190
75218.9.64.0/19218.9.64.1 to 218.9.95.254218.9.95.2558,190
76218.9.96.0/19218.9.96.1 to 218.9.127.254218.9.127.2558,190
77218.9.128.0/19218.9.128.1 to 218.9.159.254218.9.159.2558,190
78218.9.160.0/19218.9.160.1 to 218.9.191.254218.9.191.2558,190
79218.9.192.0/19218.9.192.1 to 218.9.223.254218.9.223.2558,190
80218.9.224.0/19218.9.224.1 to 218.9.255.254218.9.255.2558,190
81218.10.0.0/19218.10.0.1 to 218.10.31.254218.10.31.2558,190
82218.10.32.0/19218.10.32.1 to 218.10.63.254218.10.63.2558,190
83218.10.64.0/19218.10.64.1 to 218.10.95.254218.10.95.2558,190
84218.10.96.0/19218.10.96.1 to 218.10.127.254218.10.127.2558,190
85218.10.128.0/19218.10.128.1 to 218.10.159.254218.10.159.2558,190
86218.10.160.0/19218.10.160.1 to 218.10.191.254218.10.191.2558,190
87218.10.192.0/19218.10.192.1 to 218.10.223.254218.10.223.2558,190
88218.10.224.0/19218.10.224.1 to 218.10.255.254218.10.255.2558,190
89218.11.0.0/19218.11.0.1 to 218.11.31.254218.11.31.2558,190
90218.11.32.0/19218.11.32.1 to 218.11.63.254218.11.63.2558,190
91218.11.64.0/19218.11.64.1 to 218.11.95.254218.11.95.2558,190
92218.11.96.0/19218.11.96.1 to 218.11.127.254218.11.127.2558,190
93218.11.128.0/19218.11.128.1 to 218.11.159.254218.11.159.2558,190
94218.11.160.0/19218.11.160.1 to 218.11.191.254218.11.191.2558,190
95218.11.192.0/19218.11.192.1 to 218.11.223.254218.11.223.2558,190
96218.11.224.0/19218.11.224.1 to 218.11.255.254218.11.255.2558,190
97218.12.0.0/19218.12.0.1 to 218.12.31.254218.12.31.2558,190
98218.12.32.0/19218.12.32.1 to 218.12.63.254218.12.63.2558,190
99218.12.64.0/19218.12.64.1 to 218.12.95.254218.12.95.2558,190
100218.12.96.0/19218.12.96.1 to 218.12.127.254218.12.127.2558,190
101218.12.128.0/19218.12.128.1 to 218.12.159.254218.12.159.2558,190
102218.12.160.0/19218.12.160.1 to 218.12.191.254218.12.191.2558,190
103218.12.192.0/19218.12.192.1 to 218.12.223.254218.12.223.2558,190
104218.12.224.0/19218.12.224.1 to 218.12.255.254218.12.255.2558,190
105218.13.0.0/19218.13.0.1 to 218.13.31.254218.13.31.2558,190
106218.13.32.0/19218.13.32.1 to 218.13.63.254218.13.63.2558,190
107218.13.64.0/19218.13.64.1 to 218.13.95.254218.13.95.2558,190
108218.13.96.0/19218.13.96.1 to 218.13.127.254218.13.127.2558,190
109218.13.128.0/19218.13.128.1 to 218.13.159.254218.13.159.2558,190
110218.13.160.0/19218.13.160.1 to 218.13.191.254218.13.191.2558,190
111218.13.192.0/19218.13.192.1 to 218.13.223.254218.13.223.2558,190
112218.13.224.0/19218.13.224.1 to 218.13.255.254218.13.255.2558,190
113218.14.0.0/19218.14.0.1 to 218.14.31.254218.14.31.2558,190
114218.14.32.0/19218.14.32.1 to 218.14.63.254218.14.63.2558,190
115218.14.64.0/19218.14.64.1 to 218.14.95.254218.14.95.2558,190
116218.14.96.0/19218.14.96.1 to 218.14.127.254218.14.127.2558,190
117218.14.128.0/19218.14.128.1 to 218.14.159.254218.14.159.2558,190
118218.14.160.0/19218.14.160.1 to 218.14.191.254218.14.191.2558,190
119218.14.192.0/19218.14.192.1 to 218.14.223.254218.14.223.2558,190
120218.14.224.0/19218.14.224.1 to 218.14.255.254218.14.255.2558,190
121218.15.0.0/19218.15.0.1 to 218.15.31.254218.15.31.2558,190
122218.15.32.0/19218.15.32.1 to 218.15.63.254218.15.63.2558,190
123218.15.64.0/19218.15.64.1 to 218.15.95.254218.15.95.2558,190
124218.15.96.0/19218.15.96.1 to 218.15.127.254218.15.127.2558,190
125218.15.128.0/19218.15.128.1 to 218.15.159.254218.15.159.2558,190
126218.15.160.0/19218.15.160.1 to 218.15.191.254218.15.191.2558,190
127218.15.192.0/19218.15.192.1 to 218.15.223.254218.15.223.2558,190
128218.15.224.0/19218.15.224.1 to 218.15.255.254218.15.255.2558,190
129218.16.0.0/19218.16.0.1 to 218.16.31.254218.16.31.2558,190
130218.16.32.0/19218.16.32.1 to 218.16.63.254218.16.63.2558,190
131218.16.64.0/19218.16.64.1 to 218.16.95.254218.16.95.2558,190
132218.16.96.0/19218.16.96.1 to 218.16.127.254218.16.127.2558,190
133218.16.128.0/19218.16.128.1 to 218.16.159.254218.16.159.2558,190
134218.16.160.0/19218.16.160.1 to 218.16.191.254218.16.191.2558,190
135218.16.192.0/19218.16.192.1 to 218.16.223.254218.16.223.2558,190
136218.16.224.0/19218.16.224.1 to 218.16.255.254218.16.255.2558,190
137218.17.0.0/19218.17.0.1 to 218.17.31.254218.17.31.2558,190
138218.17.32.0/19218.17.32.1 to 218.17.63.254218.17.63.2558,190
139218.17.64.0/19218.17.64.1 to 218.17.95.254218.17.95.2558,190
140218.17.96.0/19218.17.96.1 to 218.17.127.254218.17.127.2558,190
141218.17.128.0/19218.17.128.1 to 218.17.159.254218.17.159.2558,190
142218.17.160.0/19218.17.160.1 to 218.17.191.254218.17.191.2558,190
143218.17.192.0/19218.17.192.1 to 218.17.223.254218.17.223.2558,190
144218.17.224.0/19218.17.224.1 to 218.17.255.254218.17.255.2558,190
145218.18.0.0/19218.18.0.1 to 218.18.31.254218.18.31.2558,190
146218.18.32.0/19218.18.32.1 to 218.18.63.254218.18.63.2558,190
147218.18.64.0/19218.18.64.1 to 218.18.95.254218.18.95.2558,190
148218.18.96.0/19218.18.96.1 to 218.18.127.254218.18.127.2558,190
149218.18.128.0/19218.18.128.1 to 218.18.159.254218.18.159.2558,190
150218.18.160.0/19218.18.160.1 to 218.18.191.254218.18.191.2558,190
151218.18.192.0/19218.18.192.1 to 218.18.223.254218.18.223.2558,190
152218.18.224.0/19218.18.224.1 to 218.18.255.254218.18.255.2558,190
153218.19.0.0/19218.19.0.1 to 218.19.31.254218.19.31.2558,190
154218.19.32.0/19218.19.32.1 to 218.19.63.254218.19.63.2558,190
155218.19.64.0/19218.19.64.1 to 218.19.95.254218.19.95.2558,190
156218.19.96.0/19218.19.96.1 to 218.19.127.254218.19.127.2558,190
157218.19.128.0/19218.19.128.1 to 218.19.159.254218.19.159.2558,190
158218.19.160.0/19218.19.160.1 to 218.19.191.254218.19.191.2558,190
159218.19.192.0/19218.19.192.1 to 218.19.223.254218.19.223.2558,190
160218.19.224.0/19218.19.224.1 to 218.19.255.254218.19.255.2558,190
161218.20.0.0/19218.20.0.1 to 218.20.31.254218.20.31.2558,190
162218.20.32.0/19218.20.32.1 to 218.20.63.254218.20.63.2558,190
163218.20.64.0/19218.20.64.1 to 218.20.95.254218.20.95.2558,190
164218.20.96.0/19218.20.96.1 to 218.20.127.254218.20.127.2558,190
165218.20.128.0/19218.20.128.1 to 218.20.159.254218.20.159.2558,190
166218.20.160.0/19218.20.160.1 to 218.20.191.254218.20.191.2558,190
167218.20.192.0/19218.20.192.1 to 218.20.223.254218.20.223.2558,190
168218.20.224.0/19218.20.224.1 to 218.20.255.254218.20.255.2558,190
169218.21.0.0/19218.21.0.1 to 218.21.31.254218.21.31.2558,190
170218.21.32.0/19218.21.32.1 to 218.21.63.254218.21.63.2558,190
171218.21.64.0/19218.21.64.1 to 218.21.95.254218.21.95.2558,190
172218.21.96.0/19218.21.96.1 to 218.21.127.254218.21.127.2558,190
173218.21.128.0/19218.21.128.1 to 218.21.159.254218.21.159.2558,190
174218.21.160.0/19218.21.160.1 to 218.21.191.254218.21.191.2558,190
175218.21.192.0/19218.21.192.1 to 218.21.223.254218.21.223.2558,190
176218.21.224.0/19218.21.224.1 to 218.21.255.254218.21.255.2558,190
177218.22.0.0/19218.22.0.1 to 218.22.31.254218.22.31.2558,190
178218.22.32.0/19218.22.32.1 to 218.22.63.254218.22.63.2558,190
179218.22.64.0/19218.22.64.1 to 218.22.95.254218.22.95.2558,190
180218.22.96.0/19218.22.96.1 to 218.22.127.254218.22.127.2558,190
181218.22.128.0/19218.22.128.1 to 218.22.159.254218.22.159.2558,190
182218.22.160.0/19218.22.160.1 to 218.22.191.254218.22.191.2558,190
183218.22.192.0/19218.22.192.1 to 218.22.223.254218.22.223.2558,190
184218.22.224.0/19218.22.224.1 to 218.22.255.254218.22.255.2558,190
185218.23.0.0/19218.23.0.1 to 218.23.31.254218.23.31.2558,190
186218.23.32.0/19218.23.32.1 to 218.23.63.254218.23.63.2558,190
187218.23.64.0/19218.23.64.1 to 218.23.95.254218.23.95.2558,190
188218.23.96.0/19218.23.96.1 to 218.23.127.254218.23.127.2558,190
189218.23.128.0/19218.23.128.1 to 218.23.159.254218.23.159.2558,190
190218.23.160.0/19218.23.160.1 to 218.23.191.254218.23.191.2558,190
191218.23.192.0/19218.23.192.1 to 218.23.223.254218.23.223.2558,190
192218.23.224.0/19218.23.224.1 to 218.23.255.254218.23.255.2558,190
193218.24.0.0/19218.24.0.1 to 218.24.31.254218.24.31.2558,190
194218.24.32.0/19218.24.32.1 to 218.24.63.254218.24.63.2558,190
195218.24.64.0/19218.24.64.1 to 218.24.95.254218.24.95.2558,190
196218.24.96.0/19218.24.96.1 to 218.24.127.254218.24.127.2558,190
197218.24.128.0/19218.24.128.1 to 218.24.159.254218.24.159.2558,190
198218.24.160.0/19218.24.160.1 to 218.24.191.254218.24.191.2558,190
199218.24.192.0/19218.24.192.1 to 218.24.223.254218.24.223.2558,190
200218.24.224.0/19218.24.224.1 to 218.24.255.254218.24.255.2558,190
201218.25.0.0/19218.25.0.1 to 218.25.31.254218.25.31.2558,190
202218.25.32.0/19218.25.32.1 to 218.25.63.254218.25.63.2558,190
203218.25.64.0/19218.25.64.1 to 218.25.95.254218.25.95.2558,190
204218.25.96.0/19218.25.96.1 to 218.25.127.254218.25.127.2558,190
205218.25.128.0/19218.25.128.1 to 218.25.159.254218.25.159.2558,190
206218.25.160.0/19218.25.160.1 to 218.25.191.254218.25.191.2558,190
207218.25.192.0/19218.25.192.1 to 218.25.223.254218.25.223.2558,190
208218.25.224.0/19218.25.224.1 to 218.25.255.254218.25.255.2558,190
209218.26.0.0/19218.26.0.1 to 218.26.31.254218.26.31.2558,190
210218.26.32.0/19218.26.32.1 to 218.26.63.254218.26.63.2558,190
211218.26.64.0/19218.26.64.1 to 218.26.95.254218.26.95.2558,190
212218.26.96.0/19218.26.96.1 to 218.26.127.254218.26.127.2558,190
213218.26.128.0/19218.26.128.1 to 218.26.159.254218.26.159.2558,190
214218.26.160.0/19218.26.160.1 to 218.26.191.254218.26.191.2558,190
215218.26.192.0/19218.26.192.1 to 218.26.223.254218.26.223.2558,190
216218.26.224.0/19218.26.224.1 to 218.26.255.254218.26.255.2558,190
217218.27.0.0/19218.27.0.1 to 218.27.31.254218.27.31.2558,190
218218.27.32.0/19218.27.32.1 to 218.27.63.254218.27.63.2558,190
219218.27.64.0/19218.27.64.1 to 218.27.95.254218.27.95.2558,190
220218.27.96.0/19218.27.96.1 to 218.27.127.254218.27.127.2558,190
221218.27.128.0/19218.27.128.1 to 218.27.159.254218.27.159.2558,190
222218.27.160.0/19218.27.160.1 to 218.27.191.254218.27.191.2558,190
223218.27.192.0/19218.27.192.1 to 218.27.223.254218.27.223.2558,190
224218.27.224.0/19218.27.224.1 to 218.27.255.254218.27.255.2558,190
225218.28.0.0/19218.28.0.1 to 218.28.31.254218.28.31.2558,190
226218.28.32.0/19218.28.32.1 to 218.28.63.254218.28.63.2558,190
227218.28.64.0/19218.28.64.1 to 218.28.95.254218.28.95.2558,190
228218.28.96.0/19218.28.96.1 to 218.28.127.254218.28.127.2558,190
229218.28.128.0/19218.28.128.1 to 218.28.159.254218.28.159.2558,190
230218.28.160.0/19218.28.160.1 to 218.28.191.254218.28.191.2558,190
231218.28.192.0/19218.28.192.1 to 218.28.223.254218.28.223.2558,190
232218.28.224.0/19218.28.224.1 to 218.28.255.254218.28.255.2558,190
233218.29.0.0/19218.29.0.1 to 218.29.31.254218.29.31.2558,190
234218.29.32.0/19218.29.32.1 to 218.29.63.254218.29.63.2558,190
235218.29.64.0/19218.29.64.1 to 218.29.95.254218.29.95.2558,190
236218.29.96.0/19218.29.96.1 to 218.29.127.254218.29.127.2558,190
237218.29.128.0/19218.29.128.1 to 218.29.159.254218.29.159.2558,190
238218.29.160.0/19218.29.160.1 to 218.29.191.254218.29.191.2558,190
239218.29.192.0/19218.29.192.1 to 218.29.223.254218.29.223.2558,190
240218.29.224.0/19218.29.224.1 to 218.29.255.254218.29.255.2558,190
241218.30.0.0/19218.30.0.1 to 218.30.31.254218.30.31.2558,190
242218.30.32.0/19218.30.32.1 to 218.30.63.254218.30.63.2558,190
243218.30.64.0/19218.30.64.1 to 218.30.95.254218.30.95.2558,190
244218.30.96.0/19218.30.96.1 to 218.30.127.254218.30.127.2558,190
245218.30.128.0/19218.30.128.1 to 218.30.159.254218.30.159.2558,190
246218.30.160.0/19218.30.160.1 to 218.30.191.254218.30.191.2558,190
247218.30.192.0/19218.30.192.1 to 218.30.223.254218.30.223.2558,190
248218.30.224.0/19218.30.224.1 to 218.30.255.254218.30.255.2558,190
249218.31.0.0/19218.31.0.1 to 218.31.31.254218.31.31.2558,190
250218.31.32.0/19218.31.32.1 to 218.31.63.254218.31.63.2558,190
251218.31.64.0/19218.31.64.1 to 218.31.95.254218.31.95.2558,190
252218.31.96.0/19218.31.96.1 to 218.31.127.254218.31.127.2558,190
253218.31.128.0/19218.31.128.1 to 218.31.159.254218.31.159.2558,190
254218.31.160.0/19218.31.160.1 to 218.31.191.254218.31.191.2558,190
255218.31.192.0/19218.31.192.1 to 218.31.223.254218.31.223.2558,190
256218.31.224.0/19218.31.224.1 to 218.31.255.254218.31.255.2558,190

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.